Research Finds Link Between Mexico City Air Pollution and Early Signs of Alzheimer's in Children

Children in Mexico City have developed some of the early markers for Alzheimer's in the brain's chemistry and structure due to the city's air pollution, American and Mexican researchers said.

Pollution has contributed to changes in the hippocampus where learning and memory processing take place, said Dr. Lilian Calderón-Garcidueñas of the University of Montana, Missoula.

Mexico City has had a long-standing air pollution issue. Millions of children are involuntarily exposed to harmful concentrations of fine particulate matter (PM 2.5) every day since conception, Calderón-Garcidueñas said.

The seemingly healthy children who were studied have deficiencies in attention and short-term memory, and below-average scores in Verbal and Full Scale IQ tests compared to children exposed to low air pollution, according to the research published in the Journal of Alzheimer's Disease and Parkinsonism.

"This is not one isolated change, but it is a cluster of findings pointing in the same direction," Calderón-Garcidueñas said.

While pollution is comprised of gases, such as ozone, particulate matter (PM 2.5) and organic compounds, weather also plays a role in its formation, AccuWeather Senior Meteorologist Jason Nicholls said.

"Under strong areas of high pressure, air masses can become stagnant with no flow thus trapping pollution in valleys or under inversions," Nicholls said. "An inversion is a deviation in the lower atmosphere where temperatures rise with height from the surface to a few thousand feet. Temperatures normally cool with height; this is fairly common in the mid-latitudes."

Significant exposures to air pollutants also increase the Alzheimer's risk for people over 65 years old, according to separate research released earlier this year, Calderón-Garcidueñas said.

"The most important issue is the possibility of neuroprotection," she said. "The public should also know there is no money at all for air-pollution Alzheimer's disease-associated research at the most vulnerable stage of life: when the brain is in development."

"Since the most important sources of PM 2.5 are combustion sources [gasoline, oil, diesel, etc.], you wonder why this type of information is not available to the public, and of course why there is no interest in protecting the exposed population. We have millions of children living in polluted cities in the USA and it seems nobody cares," she added.

The latest findings build on more than a decade of research conducted by Calderón-Garcidueñas on the air pollution connections. Previously, Alzheimer-like precursors were found in dogs from Mexico City.